where they execute important functions. The polypeptide chain of these proteins must cross the lipid bilayer. This presents a problem because the peptide bond is polar in nature. It turns out that in virtually all cases where an amino acid chain crosses a lipid bilayer it does so as an alpha helix. Suggest a reason why this is the case. (5 points)

Which best describes a rhinovirus? o a. a virus that causes a common cold o b. a protective shell around a virus o c. a tube the comes off a virus o d. a piece of dna transferred by a virus

Amines amides and amino acids are categories of

Which of the following statements is true regarding a basic amino acid? a.) the hydrophilic r group of a basic amino acid will be located on the interior of a protein b.) the positively charged r group of a basic amino acid could bind dna c.) the r group of a basic amino acid would only be able to form covalent bonds with other molecules d.) a basic amino acid would be considered both polar and hydrophobic e.) all of the above